Note K - Common Stock and Warrants (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Schedule of Authorized Shares of Common Stock Reserved for Future Issuance [Table Text Block]

	December 31,
	2019		2018
Conversion of Deerfield Convertible Note		1,213,606		1,167,607
Conversion of 2021 Notes		175,336		4,481,182
Conversion of 2019 Notes not subject to the Deerfield Optional Conversion Feature		3,186,770		-
Outstanding awards under equity incentive plans		5,192,222		3,704,755
Outstanding common stock warrants		2,423,077		2,527,763
Conversion of Series A Preferred Stock		-		1,112,334
In exchange for the Deerfield Optional Conversion Feature*		26,439,015		-
Possible future issuances under the Prior Purchase Agreement		9,553,046		-
Possible future issuances under equity incentive plans		84,616		648,272
Total common shares reserved for future issuance		48,267,688		13,641,913

Schedule of Common Stock Outstanding Roll Forward [Table Text Block]

	Shares of
	Common Stock
Balance as of January 1, 2018		14,657,430
Common stock sold under First ATM Agreement		762,338
Common stock issued as a result of Deerfield Convertible Note principal and interest conversion		598,568
Common stock options exercised		23,682
Common stock sold under underwritten public offering		8,333,334
Common stock issued as a result of Series A Preferred Stock conversion		2,080,000
Balance as of December 31, 2018		26,455,352
Common stock issued under the Prior Purchase Agreement		3,521,471
Restricted stock vested during the period		101,739
Common stock issued as a result of 2021 Notes principal conversion		1,499,894
Common stock issued as a result of Series B-1 Preferred Stock conversion		1,659,996
Common stock issued as a result of Series A Preferred Stock conversion		1,112,333
Common stock issued as a result of Deerfield Optional Conversion Feature conversion		2,000,000
Balance as of December 31, 2019		36,350,785